Flavonol glycosides in leaves of Spinacia oleracea

Besides spinatoside (3,6-dimethoxy-5,7,3′,4′-tetrahydroxyflavone 4′-O-β-D-glucopyranuronide), three new flavonol glycosides have now been isolated from the polar fractions of the methanolic extract of Spinacia oleracea. They have been identified as patuletin 3-O-β-D-glucopyranosyl-(1 → 6)-[β-D-apiofuranosyl-(1 → 2)]-β-D-glucopyranoside, patuletin 3-O-β-gentiobioside and spinacetin 3-O-β-gentiobioside, respectively.     

Molecular complexes of ivy and licorice saponins with sildenafil citrate (Viagra) and their biological activity

The molecular complexation of triterpene glycosides α-hederin (hederagenin 3-O-α-L-rhamnopyranosyl-(l → 2)-O-α-L-arabinopyranoside), hederasaponin C (hederagenin 3-O-α-L-rhamnopyranosyl-(l → 2)-O-α-L-arabinopyranosyl-28-O-α-L-rhamnopyranosyl-(l → 4)-O-β-D-glucopyranosyl-(l → 6)-O-β-D-glucopyranoside), and glycyram (monoammonium glycyrrhizinate) with sildenafil citrate was investigated for the first time using electrospray ionization mass spectroscopy. The glycosides form a complex in a 1: 1 molar ratio. The influence of the complex on Avena sativa seeds germination and its ichthyotoxicity against Poecilia reticulata were studied.     

Molecular complexation of α-hederin with hederasaponin C

The molecular complexation of triterpene glycosides α-hederin (hederagenin 3-O-α-L-rhamnopyranosyl-(1 → 2)-O-α-L-arabinopyranoside) with hederasaponin C (hederagenin 3-O-α-L-rhamnopyranosyl-(1 → 2)-O-α-L-arabinopyranosyl-28-O-α-L-rhamnopyranosyl-(1 → 4)-O-β-D-glucopyranosyl-(1 → 6)-O-β-D-glucopyranoside) was investigated for the first time using the methods of IR- and electrospray ionization mass spectroscopy. The glycosides form a complex in the 1: 1 molar ratio. The influence of complex on Avena sativa seeds germination and its ichthyotoxicity against Poecilia reticulata were studied.     

Five glycosides from the chinese drug ‘tong-guang-san’: The stems of marsdenia tenacissima

Five new glycosides were isolated from the Chinese crude drug ‘Tong-guang-san’: the stems of Marsdenia tenacissima (Roth.) Wight et Arn. (Asclepiadaceae). The structures of tenacissosides A-E were deduced on the basis of chemical and spectral evidence as tenacigenin B-I 3-O-β-D-glucopyranosyl-(1→4)-3-O-methyl-6-deoxy-β-D- allopyranosyl-(1→4)-β-D-oleandropyranoside, tenacigenin B-II 3-O-β-D-glucopyranosyl-(1 →4)-3-O-methyl-6-deoxy- β-Dallopyranosyl-(1 →4)-β-D-oleandropyranoside, tenacigenin B-III 3-O-β-Dglucopyranosyl-(1→4)-3-O-methyl-6- deoxy-β-D-allopyranosyl-(1 → 4)-β-D-oleandropyranoside, tenacigenin B-IV 3-O-β-D-glucopyranosyl-(1 →4)-3-O- methyl-6-deoxy-β-D-allopyranosyl-(1 → 4)-β-D-oleandropyranoside and tenacigenin B-V 3-O-β-D-glucopyranosyl- (1 → 4)-3-O-methyl-6-deoxy-allopyranosyl-(1 → 4)-β-D-oleandropyranoside, respectively.     

Molecular complexes of ivy triterpene glycosides with β-cyclodextrin

Molecular complexes of triterpene glycosides such as α-hederin (hederagenin 3-O-α-L-rhamnopyranosyl-(1 → 2)-O-α-L-arabinopyranoside) and hederasaponin C (hederagenin 3-O-α-L-rhamnopyranosyl-(1 → 2)-O-α-L-arabinopyranosyl-28-O-α-L-rhamnopyranosyl-(1 → 4)-O-β-D-glucopyranosyl-(1 → 6)-O-β-D-glucopyranoside) with β-cyclodextrin were synthesized. The complex formation was studied by FTIR spectroscopy. Toxic properties of the molecular complexes were examined.     

A furostanol glucuronide from Solanum lyratum

A new furostanol glucuronide and three known glycosides, SL-O, aspidistrin and methyl proto-aspidistrin, were isolated from the fresh immature berries of Solanum lyratum. The structure of the new compound was characterized as 26-O-β-D-glucopyranosyl-(22ξ,25R-3β,22,26-trihydroxyfurost-5-ene 3-O-α-L-rhamnopyranosyl-(1 → 2)-[β-D-glucopyranosyl-(1 → 3)]-β-D-glucuronopyranoside.     

Acetylated allose-containing flavonoid glucosides from Stachys anisochila

In continuation of our chemosystematic study of Stachys (Labiatae) we have isolated the previously reported isoscutellarein 7-O-[6″'-O-acetyl-β-D-allopyranosyl-(1 → 2)-β-D-glucopyranoside] (1) and 3′-hydroxy-4′-O-methylisoscutellarein 7-O-[6″'-O-acetyl-β-D-allopyranosyl-(1 → 2)-β-D-glucopyranoside] (4) and four new allose-containing flavonoid glycosides from S. anisochila. The new glycosides are hypolaetin 7-O-[6″'-O-acetyl-β-D-allopyranosyl-(1 → 2)-β-D-glucopyranside] (6) as well as the three corresponding diacetyl analogues of 1, 4 and 6, isoscutellarein 7-O-[6″'-O-acetyl-β-D-allopyranosyl-(1 → 2)-6″-O-acetyl-β-D-glucopyranoside], 3′-hydroxy-4′-O-methylisoscutellarein 7-O-[6″'-O-acetyl-β-D-allopyranosyl-(1 → 2)-6″-O-acetyl-β-D-glucopyranoside] and hypolaetin 7-O-[6″'-O-acetyl-β-D-allopyranosyl-(1 → 2)-6″-O-acetyl-β-D-glucopyranoside]. Extensive two-dimensional NMR studies (proton-carbon correlations, COSY experiments) allowed assignment of all ¹H NMR sugar signals and a correction of the ¹³C NMR signal assignments for C-2 and C-3 of the allose.     

Three Previously Undescribed Chlorophenyl Glycosides from the Bulbs of Lilium regale

Three previously undescribed chlorophenyl glycosides, (2,4,6-trichloro-3-hydroxy-5-methoxyphenyl)methyl β-D-glucopyranoside ( 1 ), (2,4-dichloro-3,5-dimethoxyphenyl)methyl 6-O-β-D-glucopyranosyl-β-D-glucopyranoside ( 2 ) and 4-chloro-3-methoxy-5-methylphenyl 6-O-(6-deoxy-β-L-mannopyranosyl)-β-D-glucopyranoside ( 3 ) were obtained from Lilium regale. The absolute configurations of these new finds were elucidated by comprehensive analyses of spectroscopic data combined with acid hydrolysis derivatization. (2,4-dichloro-3,5-dimethoxyphenyl)methyl 6-O-β-D-glucopyranosyl-β-D-glucopyranoside ( 2 ) can inhibit the proliferation of lung carcinoma A549 cells with an IC₅₀ value of 29 μΜ.     

Arvensoside A and B,triterpenoid saponins from Calendula arvensis

Two new triterpenoid glycosides from the aerial parts of Calendula arvensis were identified as oleanolic acid-28-O-β-D-glucopyranoside-3-β-O-(O-β-D-galactopyranosyl(1 → 3)-β-D-glucopyranoside) and oleanolic acid 3-β-O-(O-β-D-galactopyranosyl(1 → 3)-β-D-glucopyranoside) by FAB, FAB MIKE mass spectrometry and ¹³C NMR spectroscopy.     

Furostanol glycosides from Trigonella foenum-graecum seeds

Two new furostanol glycosides trigofoenosides A and D have been isolated from the Trigonella foenum-graecum seeds as their methyl ethers, A-1 and D-1. Their structures have been determined as (25S)-22-O-methyl-furost-5-ene-3β,26-diol, 3-O-α-L-rhamnopyranosyl (1 → 2)-β-D-glucopyranoside; 26-O-β-D-glucopyranoside (A-1) and (25S)-22-O-methyl-furost-5-ene-3β,26-diol, 3-O-α-L-rhamnopyranosyl (1 → 2)-[β-D-glucopyranosyl (1 → 3)]-β-D-glucopyranoside; 26-O-β-D-glucopyranoside (D-1).     

Two quassinoid glycosides and a β-carboline-1-propionic acid from hannoa klaineana

Among the polar constituents of Hannoa klaineana roots, two new quassinoid glycosides, 15-O-β-D-glucopyranosyl-21-hydroxyglaucarubolone, 15-O-α-D-xylofuranosyl(1 → 6)-β-D-glucopyranosyl-21-hydroxy-glaucarubolone, an alkaloid, β-carboline-1-propionic acid and a coumarin glycoside, scopolin were isolated and their structures elucidated.     

Structure of desacylsaponins obtained from the bark of Quillaja saponaria

A triterpenoid saponin mixture (so-called quillajasaponin) obtained from the bark of Quillaja saponaria was treated with weak alkali and two major desacylsaponins were isolated. On the basis of chemical and spectral evidence, they were determined as 3-O-β-D-galactopyranosyl-(1 → 2)-[β-D-xylopyranosyl-(1 → 3)]-β-D-glucuronopyranosyl quillaic acid 28-O-β-D-apiofuranosyl-(1 → 3)-β-D-xylopyranosyl-(1 → 4)-α-L-rhamnopyranosyl-(1 → 2)-β-D-fucopyranoside and 28-O-β-D-apiofuranosyl-(1 → 3)-β-D-xylopyranosyl-(1 → 4)-[β-D-glucopyranosyl-(1 → 3)]-α-L-rhamnopyranosyl-(1 → 2)-β-D-fucopyranoside. Diazomethane degradation providing selectively the 28-O-glycoside from the 3,28-O-bisglycoside was a useful method for the structure elucidation.     

Glycosidation at C-4 of 2-acetamido-2-deoxy-D-glucopyranose derivatives by koenigs-knorr type condensations

The condensation of 2,3,4,6-tetra-O-benzyl-D-glucopyranosyl bromide and 2,3,4,6-tetra-O-benzyl-D-mannopyranosyl chloride with benzyl 2-acetamido-3,6-di-O-benzyl-2-deoxy-α-D-glucopyranoside (1), under Koenigs-Knorr conditions, gave the fully benzylated derivatives of benzyl 2-acetamido-2-deoxy-4-O-α-D-glucopyranosyl-α-D-glucopyranoside, benzyl 2-acetamido-2-deoxy-4-O-β-D-glucopyranosyl-α-D-glucopyranoside, and benzyl 2-acetamido-2-deoxy-4-O-α-D-mannopyranosyl-α-D-glucopyranoside. Three further compounds, namely, benzyl 2-acetamido-3-O-benzyl-2-deoxy-6-O-(2,3,4,6-tetra-O-benzyl-D-glucopyranosyl)-α-D-glucopyranoside, benzyl 2-acetamido-3-O-benzyl-2-deoxy-6-O-(2,3,4,6-tetra-O-benzyl-D)-mannopyranosyl)-α-D-glucopyranoside, and benzyl 2-acetamido-3-O-benzyl-2-deoxy-4,6-di-O-(2,3,4,6-tetra-O-benzyl-D-mannopyranosyl)-α-D-glucopyranoside, were formed by reaction of the respective glycosyl halide with benzyl 2-acetamido-3-O-benzyl-2-deoxy-α-D-glucopyranoside present as contaminant in 1.     

New pregnane glycosides from Brucea javanica and their antifeedant activity

Three new pregnane glycosides, 3-O-β-D-glucopyranosyl-(1→2)-α-L-arabinopyranosyl-(20R)-pregn-5-ene-3β,20-diol (1), 3-O-α-L-arabinopyranosyl-(20R)-pregn-5-ene-3β,20-diol-20-O-β-D-glucopyranoside (2), 3-O-α-L-arabinopyranosyl-(20R)-pregn-5-ene-3β,20-diol-20-O-β-D-glucopyranosyl-(1→2)-β-D-glucopyranoside (3) were isolated along with four known compounds, 4-7, from the leaves and stems of Brucea javanica. Their structures were determined by detailed analyses of 1D- and 2D-NMR spectroscopic data. All of the compounds isolated from Brucea javanica were tested for the antifeedant activities against the larva of Pieris rapae. Compounds 1, 3, and 5 showed significant antifeedant activities after 72 h incubation.     

Secondary metabolites from Scutellaria albida L. ssp. velenovskyi (Rech. f.) Greuter & Burdet

Fourteen compounds (Fig.1) were isolated from the aerial parts of Scutellaria albida L. ssp. velenovskyi (Rech. f.) Greuter & Burdet, including four iridoids (1–4) catalpol, macfadienoside, mussaenosidic acid, albidoside; four flavonoids (5–8) hispidulin 7-Ο-β-D-glucuronide, scutellarin, xanthomicrol, eriodictyol; four phenylethanoid glycosides (9–12) verbascoside, leucosceptoside A, martynoside, 2-(3-hydroxy-4-methoxy-phenyl)-ethyl-1-Ο-β-D-glucopyranoside; the sugar ester 6′-β-D-glucopyranosyl-E-p-coumarate (13), as well as the acetogenic glucoside (Z)-3-hexenyl-1-O-β-D-glucopyranosyl-(1 → 2)-β-D-glucopyranoside (14). The structures of the isolates were established by means of NMR and HRMS spectral analyses. This is the first phytochemical study on S. velenovskyi and the first report of an acetogenic glycoside in the genus Scutellaria L. A chemical review on the isolated secondary metabolites in this study has been carried out. The chemotaxonomic value of the isolates is also discussed. Based on the literature data, the analysis revealed that the chemical profile of S. velenovskyi is close to that of the taxa belonging to the S. albida group.     

Triterpene glycosides from Astragalus icmadophilus

Six cycloartane-type triterpene glycosides were isolated from Astragalus icmadophilus along with two known cycloartane-type glycosides, five known oleanane-type triterpene glycosides and one known flavonol glycoside. The structures of the six compounds were established as 3-O-[α-L-arabinopyranosyl-(1 → 2)-O-3-acetoxy-α-L-arabinopyranosyl]-6-O-β-D-glucopyranosyl-3β,6α,16β,24(S),25-pentahydroxycycloartane, 3-O-[α-L-rhamnopyranosyl-(1 → 2)-O-α-L-arabinopyranosyl-(1 → 2)-O-β-D-xylopyranosyl]-6-O-β-D-glucopyranosyl-3β,6α,16β,24(S),25-pentahydroxy cycloartane, 3-O-[α-L-arabinopyranosyl-(1 → 2)-O-3,4-diacetoxy-α-L-arabinopyranosyl]-6-O-β-D-glucopyranosyl-3β,6α,16β,24(S),25-pentahydroxycycloartane, 3-O-[α-L-arabinopyranosyl-(1 → 2)-O-3-acetoxy-α-L-arabinopyranosyl]-6-O-β-D-glucopyranosyl-3β,6α,16β,25-tetrahydroxy-20(R),24(S)-epoxycycloartane, 3-O-[α-L-arabinopyranosyl-(1 → 2)-O-β-D-xylopyranosyl]-6-O-β-D-glucopyranosyl-3β,6α,16β,24α-tetrahydroxy-20(R),25-epoxycycloartane, 3-O-[α-L-rhamnopyranosyl-(1 → 2)-O-α-L-arabinopyranosyl-(1 → 2)-O-β-D-xylopyranosyl]-6-O-β-D-glucopyranosyl-3β,6α,16β,24α-tetrahydroxy-20(R),25-epoxycycloartane by the extensive use of 1D- and 2D-NMR experiments along with ESIMS and HRMS analysis.The first four compounds are cyclocanthogenin and cycloastragenol glycosides, whereas the last two are based on cyclocephalogenin as aglycone, more unusual in the plant kingdom, so far reported only from Astragalus spp.     

Cycloartane-type glycosides from Astragalus amblolepis

Five cycloartane-type triterpene glycosides were isolated from the methanol extract of the roots of Astragalus amblolepis Fischer along with one known saponin, 3-O-β-D-xylopyranosyl-16-O-β-D-glucopyranosyl-3β,6α,16β,24(S),25-pentahydroxy-cycloartane. Structures of the compounds were established as 3-O-β-D-xylopyranosyl-25-O-β-D-glucopyranosyl-3β,6α,16β,24(S),25-pentahydroxy-cycloartane, 3-O-[β-D-glucuronopyranosyl-(1 → 2)-β-D-xylopyranosyl]-25-O-β-D-glucopyranosyl-3β,6α,16β,24(S),25-pentahydroxy-cycloartane, 3-O-β-D-xylopyranosyl-24,25-di-O-β-D-glucopyranosyl-3β,6α,16β,24(S),25-pentahydroxy-cycloartane, 6-O-α-L-rhamnopyranosyl-16,24-di-O-β-D-glucopyranosyl-3β,6α,16β,24(S),25-pentahydroxy-cycloartane, 6-O-α-L-rhamnopyranosyl-16,25-di-O-β-D-glucopyranosyl-3β,6α,16β,24(S),25-pentahydroxy-cycloartane by using 1D and 2D-NMR techniques and mass spectrometry. To the best of our knowledge, the glucuronic acid moiety in cycloartanes is reported for the first time.     

Steroidal saponins of Asparagus adscendens

From the methanol extract of the fruits of Asparagus adscendens sitosterol-β-d-glucoside, two spirostanol glycosides (asparanin A and B) and two furostanol glycosides (asparoside A and B) were isolated and characterized as 3-O-[β-d-glucopyranosyl (1→2)-β-d-glucopyranosyl]-(25S)-5β-spirostan-3β-ol, 3-O-{[β-d-glucopyranosyl(1→2)][α-l-rhamnopyranosyl(1→4)]-β-d-glucopyranosyl}-(25S)-5β-spirostan-3β-ol,3-O-{[β-d-glucopyranosyl(1→2)][α-l-rhamnopyranosyl(1→4)]-β-d-glucopyranosyl|} -26-O-(β- d-glucopyranosyl)-22α-methoxy-(25S)-5β-furostan-3β,26-diol and 3-O-{[β-d-glucopyranosyl(1→2)][α-l-rhamnopyranosyl(1→4)]-β-d-glucopyranosyl}-26-O-(β-d-glucopyranosyl)- 25S)-5β-furostan-3β,22α, 26-triol, respectively.     

5-Methyl ether flavone glucosides from the leaves of Bruguiera gymnorrhiza

Two new 5-methyl ether flavone glucosides (7,4′,5′-trihydroxy-5,3′-dimethoxyflavone 7-O-β-D-glucopyranoside and 7,4′-dihydroxy-5-methoxyflavone 7-O-β-D-glucopyranoside) were isolated from the leaves of Thai mangrove Bruguiera gymnorrhiza together with 7,3′,4′,5′-tetrahydroxy-5-methoxyflavone, 7,4′,5′-trihydroxy-5,3′-dimethoxyflavone, luteolin 5-methyl ether 7-O-β-D-glucopyranoside, 7,4′-dihydroxy-5,3′-dimethoxyflavone 7-O-β-D-glucopyranoside, quercetin 3-O-β-D-glucopyranoside, rutin, kaempferol 3-O-rutinoside, myricetin 3-O-rutinoside and an aryl-tetralin lignan rhamnoside. The structure of a lignan rhamnoside was found to be related to racemiside, an isolated compound from Cotoneaster racemiflora, and also discussed. Structure determinations were based on analyses of physical and spectroscopic data including 1D- and 2D-NMR.     

Triterpene saponins from Cyclamen hederifolium

Five triterpene saponins never reported before, hederifoliosides A-E, and four known triterpene saponins were isolated from the tubers of Cyclamen hederifolium. The structures of hederifoliosides A-E were determined as 3β,16α-dihydroxy-13β,28-epoxyolean-30-oic acid 3-O-{[β-D-glucopyranosyl-(1 → 2)-O]-β-D-xylopyranosyl-(1 → 2)-O-β-D-glucopyranosyl-(1 → 4)-O-α-L-arabinopyranoside}, 3β,16α-dihydroxy-13β,28-epoxyolean-30-oic acid 3-O-{[β-D-glucopyranosyl-(1 → 2)-O]-β-D-xylopyranosyl-(1 → 2)-O-[β-D-glucopyranosyl-(1 → 3)]-O-β-D-glucopyranosyl-(1 → 4)-O-α-L-arabinopyranoside}, 3β,16α-dihydroxy-13β,28-epoxyolean-30-al 3-O-{[β-D-glucopyranosyl-(1 → 2)-O]-β-D-xylopyranosyl-(1 → 2)-O-[β-D-glucopyranosyl-(1 → 3)]-O-[β-D-glucopyranosyl-(1 → 6)]-O-β-D-glucopyranosyl-(1 → 4)-O-α-L-arabinopyranoside}, 30-O-β-D-glucopyranosyl-(1 → 2)-O-β-D-glucopyranosyl-3β,16α,30-trihydroxyolean-12-en-28-al 3-O-{[β-D-glucopyranosyl-(1 → 2)-O]-β-D-xylopyranosyl-(1 → 2)-O-β-D-glucopyranosyl-(1 → 4)-O-α-L-arabinopyranoside}, 30-O-β-D-glucopyranosyl-(1 → 2)-O-β-D-glucopyranosyl-3β,16α,28,30-tetrahydroxyolean-12-en 3-O-{[β-D-glucopyranosyl-(1 → 2)-O]-β-D-xylopyranosyl-(1 → 2)-O-[β-D-glucopyranosyl-(1 → 3)]-O-β-D-glucopyranosyl-(1 → 4)-O-α-L-arabinopyranoside}, by a combination of one- and two-dimensional NMR techniques, and mass spectrometry. The cytotoxic activity of the isolated compounds was evaluated against a small panel of cancer cell lines including Hela, H-446, HT-29, and U937. None of the tested compounds, in a range of concentrations between 1 and 50 μM, caused a significant reduction of the cell number.